Help tuning Tillotson 212r stock carb on a minibike.

MJL

Active Member
#1
Seems like if give it enough gas to keep it from breaking up up to the governed 5800 rpms, I get black plugs. I make a point not to let it idle for more than a few seconds. Is it possible to tune the stock carb for idle through 5800 or is this why people swap them for mikunis? I am running 93 octane ethanol free.
 

SAS289

Well-Known Member
#2
You may want to find out what jets are in the carb. The R after the 212 stands for racing. What if they have a 39 jet and a 28 low side jet? Little large for a mini bike if you ask me. Does the engine have a header pipe and an open type air filter?

What bike is this on? What gearing?
 

MJL

Active Member
#3
Got it sorted. I actually had it backwards. Pilot was lean, and main was rich. The rich main was enough to give me some bottom end, but flooded out as it tried to rev out. Realized I had an adjustable pilot thanks to another post. Opened it up a bit then leaned out the main, and things came together. Probably a bit more to be had with some fine tuning, but its a lot better. This thing is a rocket! I've loaned my Juggernaut to my son, can't wait to get it back!
 
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